Global view of biofuel butanol and economics of its production by fermentation from sweet sorghum bagasse, food waste, and yellow top presscake: Application of novel technologies

Authors: Qureshi, Nasib; LIN, XIAOQING - Guangdong University; Liu, Siqing; Saha, Badal; MARIANO, ADRIANO - Universidade De Campinas (UNICAMP); POLAINA, JULIO - Campus De Excelencia Internacional, Universidad Autónoma De Madrid & The Consejo Superior De Invest; EZEJI, THADDEUS - The Ohio State University; FRIEDL, ANTON - Vienna University Of Technology; MADDOX, IAN - Massey University; Klasson, K Thomas; Dien, Bruce; SINGH, VIJAY - University Of Illinois

Submitted to: Fermentation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2020
Publication Date: 6/3/2020
Citation: Qureshi, N., Lin, X., Liu, S., Saha, B.C., Mariano, A.P., Polaina, J., Ezeji, T.C., Friedl, A., Maddox, I.S., Klasson, K.T., Dien, B.S., Singh, V. 2020. Global view of biofuel butanol and economics of its production by fermentation from sweet sorghum bagasse, food waste, and yellow top presscake: Application of novel technologies. Fermentation. 6(2). Article 58. https://doi.org/10.3390/fermentation6020058.
DOI: https://doi.org/10.3390/fermentation6020058

Interpretive Summary: Butanol has utility as a biofuel and industrial chemical. It is preferred to ethanol as a biofuel because it contains 33% more energy on a per gallon basis, does not require use of a modified internal combustion engine, and can be blended with gasoline at any proportion. This biofuel can be produced from corn or sugarcane molasses. Unfortunately, these feedstocks are too costly for industrial production of butanol. For this reason, it is proposed to produce butanol from agricultural biomass and other less costly substrates including sweet sorghum bagasse (SSB), yellow top (YT) presscake, and food waste (FW). Following successful experimentation on production of butanol from these feedstocks, an economic evaluation was performed. It was projected that butanol can be produced for $3.26 per gallon from SSB, $2.27 per gallon from YT presscake, and $1.31 per gallon from FW. In particular, FW is landfilled and finding an alternate use will relieve an environmental issue. These butanol prices are based on the use of superior butanol producing microbial strain (Clostridium beijerinckii P260) and novel processing technologies. It is emphasized that cost competitive production of butanol would benefit the biofuels industry and reduce environmental pollution.

Technical Abstract: An economic analysis was performed to compare butanol production from three feedstocks (Sweet Sorghum Bagasse, SSB; Food Waste, FW; and Yellow Top presscake, YT) using a standard process and an advanced integrated process design. The total plant capacity was set at 170,000 -171,000 metric tons of total acetone butanol ethanol (ABE) per year (99,300 tons of just butanol per year). Butanol production from SSB typically requires pretreatment, separate hydrolysis, fermentation, and product recovery (SHFR). An advanced process was developed in which the last three steps were combined into a single unit operation for simultaneous saccharification, fermentation and recovery (SSFR). For the SHFR and SSFR plants, the total capital investments were estimated as $213.72 x 106 and $198.16 x 106, respectively. It was further estimated that the minimum butanol selling price (using SSB as a feedstock) for the two processes were $1.14/kg and $1.05/kg. Therefore, SSFR lowered the production cost markedly compared to that of the base case. Butanol made using FW had an estimated minimum selling price of only $0.42/kg. This low selling price was because FW to butanol process does not require pretreatment, hydrolysis, and cellulolytic enzymes. For this plant, the total capital investment was projected to be $107.26 x 106. The butanol selling price using YT as a feedstock was at $0.73/kg and $0.79/kg with total capital investments for SSFR & SHFR of $122.58 x 106 and $132.21 x 106, respectively.